Difference between revisions of "EMI suppression cores"

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==Selection==
 
==Selection==
 
For motor control applications it is recommended to get low to medium frequency ferrite beads for maximum efficiency.  
 
For motor control applications it is recommended to get low to medium frequency ferrite beads for maximum efficiency.  
;Preferred choices
+
;Preferred types
 
*Core material designed for low to medium frequency bands (attenuation between 1-300 MHz)
 
*Core material designed for low to medium frequency bands (attenuation between 1-300 MHz)
 
*Large enough to fit cable multiple rounds through it
 
*Large enough to fit cable multiple rounds through it
;Avoid
+
;Avoid these
 
*Core material designed for high frequency bands (above 300 MHz)
 
*Core material designed for high frequency bands (above 300 MHz)
 
*Inductor cores - will just add inductance and make things worse
 
*Inductor cores - will just add inductance and make things worse

Revision as of 22:34, 18 April 2012

Snap on ferrite beads
Toroidal ferrite bead

EMI suppression cores a.k.a. ferrite beads are an efficient way to reduce high frequency interference from wiring. Adding ferrute beads to signal & power wiring is recommended if signal reliability problems are encountered.

Selection

For motor control applications it is recommended to get low to medium frequency ferrite beads for maximum efficiency.

Preferred types
  • Core material designed for low to medium frequency bands (attenuation between 1-300 MHz)
  • Large enough to fit cable multiple rounds through it
Avoid these
  • Core material designed for high frequency bands (above 300 MHz)
  • Inductor cores - will just add inductance and make things worse
  • Iron powder cores

Most ferrite & iron powder cores look same. So if unsure about material properties, its most safe bet to purchase low to medium frequency beads from distributors such as:

  • Digikey
  • Mouser
  • Farnell

Some popular ferrite bead brands:

  • Laird-Signal Integrity Products
  • Fair-Rite

See also